Message posted by Hal on August 09, 2002 at 7:36:36 PST:

Thanks for the post.

Again, someone is throwing around terms, somewhat loosely:

HPM is not a one-shot pulse weapon. Directed energy, while RF might be included in this terminology, usually refers to lasers/particle beams. electromagnetic Pulse--EMP--is a one-shot burst of broadband RF energy that simulates, in a much smaller scale, the EMP released in a nuclear explosion.

The gist of the article concerns an EMP weapon, and these were used in Iraq during the gulf war on a cruise missile platform.

One problem with using these on a UAV is that one is likely to damage or destroy on-board electronics. Use of a directional antenna still does not solve the problem (Pogo principle) entirely because antennas have back lobes. Shielding becomes very important as does hardening on-board electronics. It could be done and was still being tested when I retired.

(The Pogo Principle refers to the famous words "uttered" by the o'possum cartoon-character, who said, "we have met the enemy and he is us.") Whenever something went awry with our tests, we would report that we had successfully demonstrated the Pogo Principle.

One HPM device that I worked on was known as TREE SHARK. This electronic warfare device, carried in a large pod that only an NKC-135 aircraft could carry, had 18 high-power (400 watt CW) traveling-wave tubes (TWT's) phased together and utilized an antenna consisting of 18 phased horn antennas (20+ db gain)which were steerable. Everything had to be in phase (same length), power lines, RF waveguide lines, etc. It was a nightmare to maintain.

We used TREE SHARK in test and evelaution operations of Naval radars--it allowed us to provide a certain level of jamming with a support aircraft stand-off range that would enable live fire (from the ship) operations with safety constraints. A different version, TREE SQUID, operated on two different RF bands. Both devices were essentially RF amplifiers. Perhaps someone has built something larger.

In Reply to: microwave weapon might be use in Iraq posted by gary on August 09, 2002 at 0:32:37 PST:

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